Method of making universal joints



Feb. 17, 1953 F. w. SAMPSON 2,528,416

METHOD OF MAKING UNIVERSAL JOINTS Filed D80. 6, 1949 2 $HEETS-SHEET 1 \jz INVENWB 3. FREDERICK M JAM/150M 5'- wm-HMM +524 .HI-S ATTORNEYS Feb. 17, 1953 w, SAMPSON 2,628,416

METHOD OF MAKING UNIVERSAL JOINTS Filed Dec. 6, 1949 2 SHEETSSHEET 2 mvnv Ton 4 I mom/ax w. .mnrson uma 4 ml. 1%

Patented Feb. 17, 1953 ID S'E'iiES .rs'r ri METHOD OF MAKING UNIVERSAL JGIN'ES Frederick W. Sampson, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mh., a

corporation of Delaware 2 Claims.

This invention relates to method of making universal joints for transmitting torque from a driving member to a driven member at substantialiy the same angular velocity at all times, even when the axes of said driving and driven memhere are non-aligned.

An object of this invention is to provide an improved universal joint wherein the torque is transmitted thru a cushioning non-metallic Inaterial, such as resilient natural or synthetic rubher, which prevents metal to metal contact be tween the driving a driven members.

Important features of the universal joint of this invention include the following. The resilient non-metallic material (which hereinafter will be referred to simply as rubber) is permanently retained compressed and distorted out of its original molded shape in a particular manner within the intervening space between an inner metal ball member and a surrounding confining spherical shell member substan ally concentric with said ball member. The outer shell member is made in two parts divided substantially at the transverse plane thru the center of its spherical surface. The rubber material is molded to shape in situ and bonded to the outer and inner sphe ical surfaces of said inner and outer members while the two parts of said outer member are temporarily located axially separated from their final positions. Thereafter the two parts of said outer shell member are forced together in an axial direction and fixed in their final concentric positions to permanently com= press the rubber material and materi lly reduce its radial thickness and force it to bulge outwardly at the unconfined end area thereof. This distortion of the rubber material out of its original molded. shape stresses the rubber in such way as to highly resist translation d splacement in any direction of the inner ball member out of concentricity with the outer shell member during use of the joint, but at the same time will permit relatively easy pivoting between said two members as axes thereof move out of alignment.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accom partying drawings wherein a preferred. embodiment of the present invention is clearly shown.

In the drawings:

Figs. 1 and 2 illustrate a method of molding the rubber material in a vulcanizing mold and simultaneously bonding it to the three main universal joint members which are located as inserts in the mold cavity. Fig. 1 is a vertical section thru the center line of the mold and joint rnebers. Fig. 2 is a transverse section taken on line 22 of Fig. 1.

Figs. 3 and a show the molded assembly as it comes from the mold of Fig. 1. Fig. 3 is a l0ngitudinal View of the molded assembly taken on line .i-3 of Fig. i. Fig. 4 is a transverse view taken. on line if-- i of Fig. 3.

Fig. 5 illustrates a method of compressing the unit shown in Fig. 3 to stress the rubber material and finally assembly the parts. The lower half of 5 shows the parts in position prior to compressing the rubber, and the upper half of Fig. 5 shows the parts in position after compressing the rubber by forcing together the two halves of the outer shell.

Fig. 6 shows the fully assembled universal joint and is taken on line 66 of Fig. 7. The shaft fixed to the inner joint member is shown in dotdash lines.

Fig. '7 is a transverse view of the joint taken on line 7-'l of Fig. 6.

Similar reference characters refer to similar parts thruout the drawings.

The inner metal ball member it has a spherical head i l and a projecting cylinderical portion 12 adapted to fit upon and be fixed to a shaft :3 (shown in dot-dash lines in 6) by welding. The spherical head Ii may have an open outer end it beyond the point where it comes into contact with the rubber material, in order to facilitate manufacture thereof.

The outer metal shell to is made in two halves l6 and i! divided on a transverse plane passing thru the center of the inner spherical head i I as shown in Fig. 6. Each half it and ll has a substantially spherical surface in contact with the rubber material and after said halves it and Ill are forced into their final positions shown in Fig. 6 the spherical surfaces of the outer shell l5 and inner spherical head H are concentric. In the form shown, the half ii opposite to shaft it is provided with a projecting cylindrical portion l8 which is suitably fixed to an adapter ring 29 as by welding at 2 l This adapter ring 255 is designed to be driving fared, as by cap screws or bolts, to the other rotating torque-carrying member onposite shaft 53. In the form shown, shaft i3 represents the propeller shaft of an automobile and adapted ring 2 represents the means by which the outer shell i5 is fixed to either the driving member of the transmission (when the joint is used at the front end of the propeller shaft) or the driven member of the differential (when the joint is used at the rear end of the propeller shaft). In either case the power torque is transmitted thru the rubber material from the outer shell [5 to the inner ball IE or vice versa, dependent upon whether the outer shell I5 is the driving member or the driven member.

An essential feature of this invention is the particular sort of distortion .under which the rubber material is held when there is no angu larity between the axes of the driving and driven members. In order to obtain this peculiar distortion, the rubber is molded and vulcanized to the inner ball member I and the two halves f6 and I! of the outer shell 15 while these three parts are in the relative positions shown in Fig. 3. Thereafter the two halves l6 and H are forced in an axial direction into abutting relationship and permanently fixed in this position, whereat the spherical surfaces of said. halves l6 and I! are concentric with the spherical surface H of ball member iii.

The molded unit shown in Fig. 3 may be obtained by locating the two halves l6 and 11' of the outer shell l and ball member H] as inserts in the vulcanizing meld as clearly shown in Figs. 1 and 2. The upper and lower mold halves 38 and 3! may be duplicates if so desired. Lower mold half 3! is provided with a removable annular end closure 32 rigidly fixed'thereto by suitable cap screws 33, of such design as to leave an annular groove 35 in which the cylindrical 'portion iii of outer shell half l1 snugly fits. Similarly upper mold half 39 has a removable annular end closure 35 fixed thereto of such design as to leave an annular groove 36 in which theshort cylindrical portion IQ of outer shell half It snugly fits. The inner annular end surfaces it of both end closures 32 and 35 are spherical and fit snugly against the spherical surface H of inner bail member lll. Also the inside bore 37 of the upper end closure 35 fits snugly over the projecting cylindrical portion l2 of ball member it. Thus the inner ball member ii! is rig-idly located as an insert in the mold cavity. The two shell halves I6 and H are held spaced apart at the transverse center line of Fig. 1, by the annular inward projection 56 which is formed integral with the two halves of the symmetrically divided separator plate 5! which lies between the mold halves 3t and 3!. Separator plate 5i is divided thru its center line in order that its two halves may be withdrawn laterally from the molded unit shown in Fig. 3 to remove same-after the molding operation is'cornpleted and themold halves fill and 3! are separated. As will be clear from Fig. l the amiular projection 53 also molds a correspondingly shaped annular groove 52 (see Fig. 3) in the molded rubber and substantially divides the molded rubber into two axially spaced symmetrical rings 68 and El, each having a normal unstressed cross section as shown in Figs. 1 and 3 prior to being distorted as hereinafter described.

The unit shown in Fig. 3 is next set upon a. spinning arbor with the snugly fitting retainer ring 76 (previously formed as shown at "H on one side thereof) telescoped thereupon as shown in the lower half of Fig. 5. Then the two outer shell halves i6 and if! are forced axially toward one another by screwing up the large arbor unit l2 until they abut at the transverse center line of the unit and their spherical surfaces are brought into concentricity with spherical surface H of ball member ill. The lower half of Fig. '5 shows all the parts in their open positions prior to .outer shell halves I 6 and I1 being forced to- 4 ward each other by the annular slidable arbor member 15 which is forced to position 15 by arbor nut 12. The upper half of Fig. 5 shows the parts in their final positions after nut 12 has been screwed home to position 12' to force outer shell half I6 to position l6 and inner ball member I0 to position II). The outer shell half 11 is held stationary by its cylindrical portion [8 abutting shoulder 8| of the arbor collar 80 and takes the compressing force exerted by arbor nut 12. While the parts are held forced together in the positions shown in the upper half of Fig. 5

its'final position shown at 13' in Fig. 6 to thereby retain the outer shell halves I6 and H rigidly fixed together in mutually abutting relation.

The two axially spaced resilient rubber rings 60 and 6| are molded to the shape shown in Figs. 1 and 3 and bonded to the contacting metal surfaces of members H1, H5 and H. Rubber rings 60 and El are radially compressed and each is bulged outwardly around spherical surface ll of ball I0 at its two unconfined end areas to its final distorted shape shown in Fig. 6 and the upper half of Fig. 5, when the outer shell halves l6 and I! are forced together as above described. The radial compression upon the rubber material is symmetrical about ball [0 hence ball I0 is urged with a high force into concentricity with outer shell [5 at all times during use of the joint. This feature will maintain ball Ill and outer shell l5 practically mutually centered during operation of the universal joint, and obviously these two members will rotate at practically the same angular velocity thruout the 3.60 degrees of each revolution even when the longitudinal axes of said two members are out. of alignment.

In operationof the joint, when shaft 53 swings in any direction out of alignment with the axis of shell [5 the consequent oscillatory partial rotation of ball liWabOllt its center relative to the outer shell I5 is taken by an internal shearing distortion inside the rubber material without any substantial tendency to pull the rubber loose from its contacting metal surfaces. Such internal shearing distortion is not concentrated at any particular point or surface in the rubber material but take place thruout the radial thickness thereof, which greatly reduces the maximum stress on the rubber material. The above described internal shearing distortion in the rubbet is further greatly facilitated by the permanent radial compression upon the rubber material due to the fact that such material when substantially compressed yields more readily by internalshear'in a direction at right angles to the compressing force. In this particular case the internal shear always occurs at right angles to the radial compressing force upon the rubber rings'fib and El thruoutthe spherical body thereof though in a somewhat different manner in different portions of the spherical rubber body.

For instance, when shaft I3 is swung in the plane of the paper as viewed in Fig. 6 the internal shear in the rubber occurs in a direction peripherally of ball ill in the particular vertical plane shown in Fig. 6. At the same time, in the horizontal plane (perpendicular to the paper as viewed in Fig. 6) the internal shear in the rubber occurs as a circular twist centered about the axis A in Fig.6, but the direction of such circular twisting at all points thereof is nevertheless at right angles to'the radial compressing force upon the rubber.

Obviously any swinging of shaft it out of align ment with the axis of outer shell 15 is accompanied by a combination of the two kinds of internal shearing distortion described in the preceding paragraph. Since both such kinds of internal shearing distortion occur in a direction at right angles to the radial compressing force upon the rubber, it will now be clear that any such swinging of shaft l3 out of alignment with the axis of outer shell E5 is taken by an internal shearing distortion in the rubber which is always right angles to the radial compression upon the rubber. Thus the rotary oscillation of ball is relative to outer shell 55 is greatly facilitated and will not be materially resisted by the oscillatory shearing distortion which takes place within the rubber material. In other words, such oscillatory shearing distortion does relatively little work upon the rubber material, consequently the rubber material will not heat up excessively during use but can readily absorb such slight amount of work and the resulting heat will be readily conducted away by the contacting metal parts and be lost to the surrounding air.

It will be noted (see Figs. 5 and G) that the radial compression upon rubber rings 69 and 81 flattens out the radial depth of the rubber material and causes it to bulge out laterally at the unconfined end areas thereof. This causes the rubber material to partially or completely fill the central peripheral molded groove 52 therein (see Fig. 3) to the desired extent, dependent upon the degree of radial compression and the dimensions of the outer shell l5 and inner ball it. At the unconfined annular end areas cc and Si the rubber is forced to bulge outwardly (as shown in Fig. 6) from its original molded shape shown in Fig. 3. The rubber of course tends to return to its original molded shape, thus even though the central portions of rubber rings 59 and GI are under a permanent high radial compression the rubber fibers extending around the bulges at 911 and 9! have been necessarily considerably stretched and are maintained under a permanent tension. This tension is sufiiciently high to substantially prevent any further outward bulging of the rubber at these end areas 98 and 9! and hence highly resist any force tending to displace inner ball it out of concentricity with outer shell During the oscillatory partial rotation of ball is relative to shell is described above, the distortion of the rubber bulges at end areas 963 and ti is not materially changed because these bulges obviously are capable of a sort of rolling action between the adjacent metal surfaces.

Power torque is resiliently transmitted from the outer shell 5 to the inner ball it, or vice versa, by an internal shearing stress throughout the body of rubber rings Eli and ill, which shearing stress of course extends around said rings in the circular direction of the torque. Since the rubber is strongly bonded by vulcanization to the contacting metal surfaces of shell l5 and ball in and is also highly compressed against said metal surfaces, this joint is capable of carrying a relatively great torque load for its size. The degree of hardness or softness of the resilient rubber rings Eli and El may be varied as desired to suit the particular working conditions under which the joint is used. The term rubber as used herein is intended to include vulcanizable compounds of natural or synthetic rubbers or other resilient material having similar physical characteristics.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. The method of making a universal joint comprising: providing a torque-carrying interior member having a substantially spherical surface and a torque-carrying exterior member having a substantially spherical surface adapted to surround said first spherical surface in spaced relation therewith, said exterior member being formed in two parts adapted to be moved axially relative to said interior member to bring said interior and exterior spherical surfaces into substantial concentricity, locating said interior member as an insert in a vulcanizing mold, locating as inserts in said mold said two separate parts of said exterior member in mutually axially spaced relation with one another on opposite sides of said spherical surface of said interior member, then molding elastic rubber material in the intervening space between said spherical surfaces and thereby simultaneously bonding said rubber material to said spherical surfaces, removing the vulcanized unit from the mold, then forcing said axially spaced parts of said exterior member toward one another until said interior and exterior spherical surfaces are forced into substantial concentricity and permanently fixing said parts together to permanently retain said rubber radially compressed and axially elongated from its original molded shape.

2. The method of making a universal joint comprising: providing a torque-carrying interior member having a substantially spherical surface and a torque-carrying exterior member having a substantially spherical surface adapted to surround said first spherical surface in spaced relation therewith, said exterior member being divided into two separable parts, locating said members as inserts in a vulcanizing mold in correct final relative positions except that the two parts of said exterior member are located axially separated a substantial distance, then molding in itu elastic rubber in the intervening space between said spherical surfaces of said interior member and the two parts of said exterior member, then removing the vulcanized unit from the mold, then distorting the molded shape of the rubber by forcing the axially separated parts toward each other until the spherical surfaces of said inner and outer member are brought into substantial concentricity, and thereupon permanently fixing said halves together.

FREDERICK W. SAMPSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,867,540 Rosenberg July 12, 1932 1,940,884 Rosenberg Dec. 26, 1933 2,098,703 Geyer Nov. 9, 1937 2,142,784 Guy Jan. 3, 1939 2,442,640 Dunn June 1, 1948 

